High Confidence - Biological Membranes Flashcards Preview

A-Level Year 1 & AS Biology OCR A > High Confidence - Biological Membranes > Flashcards

Flashcards in High Confidence - Biological Membranes Deck (13)
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1
Q

What factors affect membrane permeability?

A

Solvents

Temperature

2
Q

How would you increase the permeability of a membrane with a solvent?

A

Increase its concentration.

3
Q

What type of molecule is a messenger molecule and how does it travel?

A

Hormone.

Blood.

4
Q

The path from an area of high concentration to an area of low concentration is called what?

A

Down the concentration gradient

5
Q

What sort of process is diffusion?

A

Passive - no energy is needed for it to happen.

6
Q

What is the water potential of pure water?

A

Zero.

7
Q

Name three types of solutions in relation to water potential and cells.

A

Isotonic

Hypotonic

Hypertonic

8
Q

Diffusion using carrier and channel proteins is called what?

What type of process is it?

A

Facilitated diffusion.

Passive.

9
Q

How does a carrier protein work?

A

A large molecule attaches to a carrier protein in the membrane.

The protein changes shape and releases the molecule on the opposite side

10
Q

Define active transport.

A

Movement of molecules against a concentration gradient.

11
Q

What proteins does active transport use and what is important about the process?

A

Carrier proteins.

Requires energy (ATP)

12
Q

What does the outer membrane do for mitochondria?

A

The outer membrane keeps substances (enzymes) needed for respiration together.

13
Q

How could you investigate the effect of temperature on membrane permeability?

A

Cut 5 equal-sized pieces of beetroot.
Rinse to remove any pigment released during cutting.
Add each piece to a separate test tube with 5cm3 of water in each.
Put each test tube in a water bath of varying temperatures for the same amount of time.
Remove the pieces, leaving just the liquid.

Colorimeter…